builtins.c (fold_builtin_memory_op): Use the alias oracle to query if the memory regions for memmove overlap.

2009-08-31  Richard Guenther  <rguenther@suse.de>

	* builtins.c (fold_builtin_memory_op): Use the alias oracle
	to query if the memory regions for memmove overlap.
	* tree-ssa-alias.c (ptr_deref_may_alias_decl_p): Relax the
	asserts on pointers, instead deal with odd trees.
	(ptr_derefs_may_alias_p): Likewise.
	(refs_may_alias_p_1): Constructor bases also never alias.

From-SVN: r151241

1 files changed, 7 insertions, 51 deletions

diff --git a/gcc/builtins.c b/gcc/builtins.c
index 1a9e966..ed97d48 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -8990,6 +8990,8 @@ fold_builtin_memory_op (location_t loc, tree dest, tree src,
 
       if (endp == 3)
 	{
+	  ao_ref srcref, destref;
+
 	  src_align = get_pointer_alignment (src, BIGGEST_ALIGNMENT);
 	  dest_align = get_pointer_alignment (dest, BIGGEST_ALIGNMENT);
 
@@ -9012,62 +9014,16 @@ fold_builtin_memory_op (location_t loc, tree dest, tree src,
 	    }
 
 	  /* If *src and *dest can't overlap, optimize into memcpy as well.  */
-	  srcvar = build_fold_indirect_ref_loc (loc, src);
-	  destvar = build_fold_indirect_ref_loc (loc, dest);
-	  if (srcvar
-	      && !TREE_THIS_VOLATILE (srcvar)
-	      && destvar
-	      && !TREE_THIS_VOLATILE (destvar))
+	  ao_ref_init_from_ptr_and_size (&srcref, src, len);
+	  ao_ref_init_from_ptr_and_size (&destref, dest, len);
+	  if (!refs_may_alias_p_1 (&srcref, &destref, false))
 	    {
-	      tree src_base, dest_base, fn;
-	      HOST_WIDE_INT src_offset = 0, dest_offset = 0;
-	      HOST_WIDE_INT size = -1;
-	      HOST_WIDE_INT maxsize = -1;
-
-	      src_base = srcvar;
-	      if (handled_component_p (src_base))
-		src_base = get_ref_base_and_extent (src_base, &src_offset,
-						    &size, &maxsize);
-	      dest_base = destvar;
-	      if (handled_component_p (dest_base))
-		dest_base = get_ref_base_and_extent (dest_base, &dest_offset,
-						     &size, &maxsize);
-	      if (host_integerp (len, 1))
-		{
-		  maxsize = tree_low_cst (len, 1);
-		  if (maxsize
-		      > INTTYPE_MAXIMUM (HOST_WIDE_INT) / BITS_PER_UNIT)
-		    maxsize = -1;
-		  else
-		    maxsize *= BITS_PER_UNIT;
-		}
-	      else
-		maxsize = -1;
-	      if (SSA_VAR_P (src_base)
-		  && SSA_VAR_P (dest_base))
-		{
-		  if (operand_equal_p (src_base, dest_base, 0)
-		      && ranges_overlap_p (src_offset, maxsize,
-					   dest_offset, maxsize))
-		    return NULL_TREE;
-		}
-	      else if (TREE_CODE (src_base) == INDIRECT_REF
-		       && TREE_CODE (dest_base) == INDIRECT_REF)
-		{
-		  if (! operand_equal_p (TREE_OPERAND (src_base, 0),
-					 TREE_OPERAND (dest_base, 0), 0)
-		      || ranges_overlap_p (src_offset, maxsize,
-					   dest_offset, maxsize))
-		    return NULL_TREE;
-		}
-	      else
-		return NULL_TREE;
-
-	      fn = implicit_built_in_decls[BUILT_IN_MEMCPY];
+	      tree fn = implicit_built_in_decls[BUILT_IN_MEMCPY];
 	      if (!fn)
 		return NULL_TREE;
 	      return build_call_expr_loc (loc, fn, 3, dest, src, len);
 	    }
+
 	  return NULL_TREE;
 	}